SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4f5edafbf83e8ca6f889951d876d76ccda982950083472126a9716077f57efe2' 
  AND token = 'pmCsgvujg6FRBUYHH5YEOGKscSIaR+8JYgEMqwMRBvU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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