SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '88982880b84ffe3937a272c5b7379dfff3d4da36e148f155818f4d16e2b541fc' 
  AND token = 'btfRDqLYaYy4XLBGFInhJGC2NqmFDqgSxBVwC+jeM/w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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