SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e9552b7211cfc47950472fe338e5d6323b075c1d967eef9a1476b6bc4992e002' 
  AND token = 'Fpm7grLoIvUIOnZsf/bUHMLkkTopzCu9i6B/7ct0LrQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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