SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '0f2ef9259ad1a75d7cae66234131f1a46b1b959b3d8d65481785fc1438e2aefe' 
  AND token = '2It/uhRGU5hiB1vokkavmIeWZmyJ1dFLiiH++fhQNr4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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