SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '14317ef3319ec8faa2d57d26ec5c883c4c69c2ca3d940b8e4deaa97becae1dd1' 
  AND token = 'CBJDv5S693OmmRtIpOq4MXndDWyABmT2oNj7+OC4YAo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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