SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6f4b288e3a76eb19912139ef96d1a82ef44f82610184a9d2c6a517a60c2d93bc' 
  AND token = 'OtnP2i5Bk6gz4w061mRl+KoppYv2qunnybiTgcXGadA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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