SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'dff1c422f41dc40d72ced7c35e2d7c9762910ae1acd946d4a39b703afcb3aeea' 
  AND token = 'C45ojGUSPMuzmA/c0yRK7R5HxksPfo65QqO3f140nF0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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