SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5b978d452a4c503f6b2a8ef25360e613d184b9e01d679867edc6931e0b0f71b0' 
  AND token = '0k/v8jJpzwhFmg2JnKg+A1LRZxSamT6IZb5adO2NCI8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}