SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9ca92fc23e2183cf03263a36583d1adf84de540cbf0d45774c9881573e891c1d' 
  AND token = 'qR6p5qfBNSHkJQt7lzCjejanidVKsRGvYLLY1j/EGho=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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