SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '9855240291854193bcd6e885dcf2c1c034fb4775eb57aebd26232d1d2de2cb97' 
  AND token = 'LsZgx6mL2/vay12sAN7kNSBm515RTGjRnUiM/5JpkHQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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