SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '92810e8582b92cd9930d7dc3f05d3c8c342eb98e54e05672be0e2d136be92d07' 
  AND token = 'fNSLgp4hsDzQJgVQOaPCQ9GRGqJD5JvzsMu4EZDlKGA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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