SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3fc0694682cec2eb53cc6ae2e509f3b977e1f86581473cf2c3af07ca8d9e0b58' 
  AND token = 'ZrVw3UX2W9EIHhOceGx+ZLSi6BYvDlo4cKUR1jCBrKk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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