SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '194b2b5d05609672aa25f3ff2eb7634db792dd2c7392e53f25089ddc03a0f83f' 
  AND token = 'jz0TW8AHrumqR+IHVYM9k3OsSze3wFWDFR4D63kwOf8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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