SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1a44cb1153c2f26bffb332a7180f2fd888ec1e5015f4581e70ab2fe4710da9c2' 
  AND token = '6jwKcioyZLkm5ZWsjxDtatQvmspwDdeFGQtcc2F4wcE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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