SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '955be413d1e2ce1662a9d8500ec4635c7fee2a52256fcb262a63009836677819' 
  AND token = '+kbeSmBE4AdbuxhSZIWOr/W8KcMHOn2UgSQ2A8tHB2s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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