SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dd443b29484c61f3e963759661cba11fa117410092f9b865ecd15e0dd4d81f4d' 
  AND token = 'V4QtYOFdYWhzPh/6mJg3uEbJmyd8IKpFLCCBBIms3PA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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