SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '631a187d4cab400fbce1df6464de1df4a87a229f9e3de36fed1969d32637f14a' 
  AND token = 'BIw6Gyp3RXtgH7nBrf8BcwWh2UdgUpL5N8dE2j96uZw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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