SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9a99806c7c42e8b29ab8e8d13e57178460d33243c12088fb3864980c82ef5dc8' 
  AND token = '3Qk9YEkmQR/kh0VkT02u3FgBSGz1L+Br1FXOA+lRN4U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00012

JSON explain

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