SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c70edbcfcaadf676845531e8e640d67789c257cf047c0a5e7d2ff03aca5c4d40' 
  AND token = 'kqoBxelU7PhwwShhmmY6aQYpGKnG6TRaWJKyS/SQQyY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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