SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7a0bfe3bac084db447e8381d8fb9233ef2ca2bcd069586edc5b6b076762b7e99' 
  AND token = '80uZvvcfKgW3ZJ4lMxY+C4K/5mPz9yBr1Vy09hEV31c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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