SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f56ae1d13a9fbd400eff336c0e09057560a5236ab01dacc17657300a9e8b7146' 
  AND token = 'Ervv14j4OXTVmtUDe7Yz+LuVnTzfk7hicnXD5Rfx2sM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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