SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '96534824d09fc14a6d8be5480513e29cb69b336b5da59979d16c709ea1567b70' 
  AND token = '+RiyPCTvEQv6QMHBrzPEmG+s2LJKMmG4i7Z2xVXS4ZI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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