SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'df340d069cbb090bb4b67ea06233ff04d2dd7a6289c6a6f2d626bb00143d8dd4' 
  AND token = 'UclT0aV1LNw1n6EZF67guaY6q4C/Lp0OZjw4+r1s8W8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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