SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '47544e2d5df2d6a58dddeca570c228b4d822e1907bdd94a63dcc89c46312d979' 
  AND token = 'p1TslyphTe2DZDncmSdI6qXr33YA5g/YvhAVcf0qPH8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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