SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b948200417288e251776169b6d73138867e577c14de2c57c1daf4cb49f609084' 
  AND token = 'oNhkOsVSMGuRGyA1/qf0ak77Ln1wMuyh/58ymcyYkrk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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