SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ceee66836f0904286005031e7828cca9a553393cc95a2bfc65073fbd897a7497' 
  AND token = 'MW6cylTOaA5cUAJlTkOsioSYa5qUizVoEIOIKhO5C9A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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