SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bd998e79b43554639536eb527ce752d0ba72f2cb6ecdc63d0faf164e51bef8d5' 
  AND token = 'moHXKJbAcMmA0uvD4eZo6H8hiTOphmGtbCdu2Cwa+Vs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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