SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5e4eb2af666eb0535c5fffb796107129590fa081919213e1f0e80305267767b1' 
  AND token = 'K5nUN/HnH+VHpdcrYxmarre32TSO/0gslzuX3T7qd08=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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