SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f244fca6330e48e3f8fce89475a8b0d610c2853ebbd2d70ec1526ed1d96856d2' 
  AND token = '3qGppKKJHNBGBA7d5IkReOMEBtwmECXFcNN62vrVTX4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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