SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3c579e733905cd068fd02507c173bea449465540001cb4629122f2b82f63bade' 
  AND token = 'Glyx5oZ32zSnuDNsWCmkSKc4PMw3ULQGHSNRj+vCCpc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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