SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '23fdf6aba1566faaa656589a2323d72f3199dce325554796fa6fd8dfeda36bdf' 
  AND token = 'bHJnqrDQV4PbaEJWaTkuWAOGNNxyX9xfutveSdpV7GI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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