SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '557aa0f375b3cfed746a81edee2dbe1e2ee8c472ef92fe6e20b91f0a28786667' 
  AND token = 'ig6HnpJaDCyD/fiC/JqvAkmpuPOUQdyOwpTP4+a5NPY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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