SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a9fe03fc02815dbe725343337d5d2cd764e3c5e93694834094b9a880b9e08fdc' 
  AND token = 'EkNrxfJ7MNDLuUrB9e3asmwHyJ8Xn16/AnW9DKtIxDI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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