SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5072acd7e33b98accd23389a9dcb18295cbe21a724ec62133e764d4ae1aab5b0' 
  AND token = 'm33IReDyHwoMjZRcsY/LwI3Bjrualnd4JdUOLFl+gDY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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