SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e00aaa1591c99ff10fea2a583f664ab1cc28939c90346444e3e0f7fb08256a29' 
  AND token = '3T1fpazh4lbDlz4yxcSpXOpL41dIrELdUVxQ9hchNGQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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