SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8ecc4b73acb651ccd85478cf0e0bc82d970f3161e6766520ab7171134d71135c' 
  AND token = 'cKHyTMT1o27xCbQHVPeFpS0UsjwMDFNWIBH/w2Y0umo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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