SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '34779f716e542e55d1199432cfe8df4a9d4d6ed49122f71109aaa8de33069f6a' 
  AND token = 'VBMH2gGqtq5XwwPYGWeGXzAUuPCQFTNaW1lH+c5Smhk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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