SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6be4d19bf7b30c20194ee89e4d0c03c3b4552d99a6f26a9151dc1b4c946f88d3' 
  AND token = 'hOF8LfCVqImUcc+FwHWbuebROPmsCGtnLMQwrHAl694=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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