SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5d1ad08ff155f7fe2c3a50aa4f4ab2fd7c80ec0538ae86694a5ad1192969c825' 
  AND token = 'iYX4maHhx+3e/CLMi1LCBuPDnrLNmcAhX6OIpFK45Sk=' 
  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"
    }
  }
}