SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '574cf7f1ed8b5ea82d2a134922f96bfded906a0e192f61706b738882a1150e0d' 
  AND token = 'JJxNVFQkNBj7NH/kbH03R+DahKQMbzTP15AILp7zGgE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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