SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5fc1b4c6b1b686c49ad375fc98b45e25a6e3dba7538193cf1fecc139ba32e1c2' 
  AND token = '9jopVImkXYUmh5o+Jgt/oKev6L1jlipzsERGXcL6DjI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}