SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f87ddb7d2f536c2c1889fed92e518622d0b3071c5de13641408113b2f1b0c8fa' 
  AND token = 'nIV7KW/xn7llGFI26Z0du4wVBzx3+mbv9fEgDTlDm5s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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