SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a162314576f65c13efa6f823d5dceb9c8c3f31aeaf86d2911d1e251da524a04f' 
  AND token = 'zcLbIVeIs26ZcijTKIX+QJ4aL1C9EjuR+CIBuNXCcAU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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