SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c1615695f242d2f9e6a746d3aa473ce0c52981071721623febcc68d380c3c7b5' 
  AND token = 'GBghwneSYPtD3ni8M8QaSRuBrjCsEYqdLw6+HnUCoN8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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