SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3eefebfeb0c7a8a0f66cb0d58cc833b0beeee721a9be49a4468328823d5e888c' 
  AND token = 'UChImeGnz9X59yCi+e2y+lCy7feyAi6NR9e3dmDO0cY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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