SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ee9db52034aa07674167886822613e24f657ab22b4140ce3117ec971d354bd53' 
  AND token = '13I6CftFLwzrGqmikHEONR/hkxY3VI6pV0AQ2rpeGlA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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