SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c49fce50e7bcd515fec7ebd916c98765aa6101e3744b1b51c49653f957fe0a0c' 
  AND token = 'AMpghG+j8DGMqM+QKS89cWBwyY2onUVeqBvsBEiBeBM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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