SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '98e53e4dc1128cc40a661e0b21d029bd9f8165e47b7229c95bb8b1acaf2842f3' 
  AND token = 'RU/DniJH/QD5msd/UkFVrWMCNHGxEmYwF+c+H7h1JG8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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