SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '41a8f08ad89e273787127f6db408f0e72295e8d7c69659654b7952246317be74' 
  AND token = 'FVT6Kegaq6fcbyPpFgP1JdY2PYc/W/l/M+Eo3iD3Tzw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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