SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '17de9c343fe26c53ced7245a58daba2412ee3f4be56adfc0148e16d00f17e636' 
  AND token = 'CxCHMllqsEf6hE60kx3FMy1l4i+dYzlSr2WzcQ4rsCA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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