SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2b052bf2f4a1196cfffa8e5392c16858b335974a0f73fed3211d2c9442a26b7c' 
  AND token = 'Dgu4XskhmOwQWyxwMoVQlYwykaPZgNV+hqOGZy9Z6b8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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