SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '293794c7cd03e27dfba9a8fad704359a99543d16e483a30c63d5eb158880a35c' 
  AND token = 'Yjx5seJpRz4G2m+vlcbFd45biDpITWwLlCMfqOoatow=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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