SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a53a2583d1ca69b49933af263010c430528ce74635a7b326c6d7a2981c8c8635' 
  AND token = 'l+XDPaH2Ph06doZiOs0Brozo/DPXLuBWLopcmBq54RM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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