SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b0192256d5d78f3d6dae147c82816555bd828ac22e7bf8f57e8cca32bfddf04f' 
  AND token = 'WC4RO3tP48jLm6uEzXa4FFMEKGdL1gfmE5muqkizggY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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