SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '978a20f541f6cea7f68331f548fc8fc9717c3e6d997f31c73d5e2df5e58a94a5' 
  AND token = 'saEeoGv7XtQjajiMXxViSsRBxBagvix9EdbdcNyPlzY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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