SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5ee976633f4138d2e9cedb79a9bc89ab76332914784bbb8c8dba75750437aa83' 
  AND token = '5x8L1bmbo23rkvdp6lHps/4+Q9uUiyGP0oZND0x+rcc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}