SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd9a1b5b84759588d7d590c6107f16038a5a0a5fc93a1aaccde8db1c0a5ef4652' 
  AND token = 'OcBw+/4OEJmkqmmZL4mY/m2TJ8XMhOdmi/uLAOFCtQs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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