SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd7551950b612ab8421be8d00e7cccecc61b00d6678a78f315aa7411dc421d267' 
  AND token = 'Oe8aqHBC+A2wAksd0XuX+Dw9x3IEYSLL5g4pcgMkJNo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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