SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5f8bdb6494e7b9656413ac2f85216d235d3d261199ed85852cd6cf50e9a6f562' 
  AND token = 'nXs4I2jSlWwkqpeKYzb2uCxxDzdZuIZbYVjAJUP5mFU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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