SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bed9143ca277827cbb0b990f3e9cb8b4d5bcfd30991f680ae87b90a63358a4b5' 
  AND token = 'FZalzj8lt2ygGZDngx1PdcJyAwHMIXGI0pgRQhQeBkI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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