SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '15629107230c2d886177dfd603ba47937cce774e93d097b004a360508bfefae8' 
  AND token = 'ORar9lIkfOUaxytBakh+576fRmJMEhIrUrRY5ZIuq/s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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